This is one simple script to parse a list of fqdn-hostnames if you need only the ip-addresses.
You can customize it in any way you want just like extending for ping-requests or generating new lists from it.
while read line; do host $line | awk '{print $NF}' | grep -oE "\b([0-9]{1,3}\.){3}[0-9]{1,3}\b"; done < list.txt
Hope you like this short example.